湖北省马尾松精准适宜性空间分布

马尾松作为南方主要的造林树种,研究其适宜性精准空间分布对其退化评价、造林选地等具有生产指导价值。本研究采用多元线性回归克里金模型利用R语言对湖北省降雨量、气温等15个气象因子进行30×30m的空间插值,插值结果作为气象因子空间变量,插值的交叉检验结果≥90%。利用30m的DEM提取坡度、坡向、高程3个地形因子空间变量。首先利用年均温、最冷月最低温、年降水量、高程、土壤类型等限制性因子进行空间叠加排除不适宜的空间单元,然后在可能适宜的空间单元内,再基于18个空间变量和294个样方数据,利用最大熵模型(MAXENT)计算每个格网的适宜性指数,最后按照适宜指数进行适宜性分类。区别于以往大尺度区域研究,其结果是落实到地块尺度的精准计算。结果表明:ROC模型的评价效果达到较好水平(ROC=0.826),高程、土壤、降雨相对标准差、最湿季降雨量、坡度、年均温为湖北省马尾松的适宜性主要影响因子,马尾松中、强适宜区主要分布在湖北省东北部及中北部地区,主要分布在高程低于1200m、坡度在40°以下、年均温13-18℃的区域,中等及以上适生区面积共计4.65万km~2,占湖北省总面积的25.01%。     

中稻田三种飞虱的捕食性天敌优势种及农药对天敌的影响

对两优0923非防治的中稻田白背飞虱、灰飞虱和褐飞虱与其天敌间的关系,采用灰色关联度法、生态位分析方法,对盆拍法调查的3种飞虱与其捕食性天敌在数量、时间和空间三方面关系进行分析,对每一种天敌对应的关联度、生态位重叠指数和相似性比例等参数标准化后的密切指数相加,按照密切指数值之和大小排序,评判3种飞虱捕食性天敌优势种.并用同样方法分析常规防治田农药对飞虱捕食性天敌的影响,以期为合理施药,科学保护和利用天敌优势种提供科学依据,其结果是,非防治田白背飞虱前三位天敌是条纹蝇虎、草间小黑蛛和锥腹肖蛸;灰飞虱的是八斑球腹蛛、茶色新园蛛和锥腹肖蛸;褐飞虱的是纵条蝇狮、四点亮腹蛛和黑肩绿盲蝽.防治田白背飞虱前三位天敌是条纹蝇虎、草间小黑蛛和锥腹肖蛸;灰飞虱的是拟水狼蛛、四点亮腹蛛和草间小黑蛛;褐飞虱的是黑肩绿盲蝽、拟水狼蛛和四点亮腹蛛.盆拍法的防治田和非防治田之间3种飞虱前三位的相同天敌,白背飞虱完全相同,灰飞虱没有相同天敌,褐飞虱的是黑肩绿盲蝽和四点亮腹蛛.飞虱与天敌在时间和数量关系上,扫网法的防治田和非防治田之间3种飞虱前三位的相同天敌,白背飞虱的是锥腹肖蛸和四点亮腹蛛,灰飞虱完全相同,褐飞虱的是纵条蝇狮和条纹影虎.两种稻田的差异主要是农药杀伤了飞虱,使飞虱数量减少,并对天敌有一定杀伤力,进而影响到天敌的发生规律.非防治田的盆拍法和扫网法之间,3种飞虱前三位相同的天敌,白背飞虱的是锥腹肖蛸,灰飞虱的也是锥腹肖蛸,褐飞虱的是纵条蝇狮.防治田两调查方法结果之间,白背飞虱的是锥腹肖蛸,灰飞虱和褐飞虱前3位天敌中没有相同天敌,其差异主要是两法调查稻株的部位不同所致.     

肠道内产丁酸细菌及其产物丁酸生理功能的研究进展

产丁酸细菌是利用糖类发酵产生丁酸的一类细菌,代表种是丁酸梭菌。在动物及人类肠道内存在的产丁酸细菌主要是梭菌属、柔嫩梭菌属、罗斯式菌属、真菌属及丁酸弧菌属。本文一方面介绍部分肠道内产丁酸细菌的种类、特点及膳食纤维的摄入和肠道益生菌对产丁酸细菌的影响,另一方面对其主要代谢产物丁酸在体内的生理功能进行探讨,以期为产丁酸细菌的应用及产品开发提供理论依据。     

长江经济带耕地利用绿色转型与城乡融合耦合协调发展的时空格局研究

在深入实施国家粮食安全战略,协同推进经济高质量发展和生态环境高水平保护背景下,探究耕地利用绿色转型与城乡融合发展的耦合协调是解决耕地保护、生态保育与经济建设之间冲突的关键。从人地关系视角剖析了耕地利用绿色转型与城乡融合发展的耦合机理;通过解读耕地利用绿色转型与城乡融合发展的内涵构建了相关评价指标体系,并以长江经济带130个地级市为例,基于2000、2005、2010、2015和2020年数据,运用耦合协调度模型分析耕地利用绿色转型与城乡融合发展耦合协调的时空格局特征。结果表明:(1)2000-2020年长江经济带耕地利用绿色转型指数由0.208增至0.294,增幅为40.802%,呈现"东北部高西南部低"的分布特征。(2)2000-2020年长江经济带城乡融合发展指数由0.465增至0.492,增幅为5.858%,呈现"中东部高西南部低"的分布特征。(3)2000-2020年长江经济带耕地利用绿色转型与城乡融合发展的耦合协调度由0.556上升到0.612,增幅为11.065%,呈现"中东部高西部低"的分布特征;耦合协调类型从基本协调型转变为中度协调型。各子系统间的耦合协调程度差异较大,耕地利用绿色转型各子系统中,模式转型与城乡融合发展的耦合协调度较低;城乡融合发展各子系统中,人口融合、空间融合与耕地利用绿色转型的耦合协调度较低。(4)耕地利用绿色转型中的模式转型,城乡融合发展中的人口融合、空间融合是长江经济带发展需重点关注的问题。研究结果可为长江经济带耕地资源的优化利用、生态保护以及城乡融合发展提供借鉴。     

实验动物屏障系统微生物动态状况

目的研究运行中的实验动物屏障系统微生物的情况。方法采用沉降菌法、棉拭子法等方法,研究运行中的屏障系统不同区域、不同环境指标下屏障系统内微生物的状况。结果动态下的屏障系统微生物情况与国标GB14925-2001中静态环境有较大不同,动物饲养室和动物实验室沉降菌浓度远高于静态要求;辅助区域在规范化消毒及严格管理的情况下,能达到国标要求。屏障系统的微生物情况存在一定的昼夜变化规律,在晚间出现峰值。结论合适的换气次数可有效控制实验动物屏障系统的沉降菌浓度;加强消毒及硬件的管理,是屏障系统内环境稳定的保障。     

The Ecto-enzyme CD38 Is a Nicotinic Acid Adenine Dinucleotide Phosphate (NAADP) Synthase That Couples Receptor Activation to Ca2+ Mobilization from Lysosomes in Pancreatic Acinar Cells

Nicotinic acid adenine dinucleotide phosphate (NAADP) is the most potent Ca²⁺-mobilizing intracellular messenger and is linked to a variety of stimuli and cell surface receptors. However, the enzyme responsible for endogenous NAADP synthesis in vivo is unknown, and it has been proposed that another enzyme differing from ADP-ribosyl cyclase family members may exist. The ecto-enzyme CD38, involved in many functions as diverse as cell proliferation and social behavior, represents an important alternative. In pancreatic acinar cells, the hormone cholecystokinin (CCK) stimulates NAADP production evoking Ca²⁺ signals by discharging acidic Ca²⁺ stores and leading to digestive enzyme secretion. From cells derived from CD38^−/− mice, we provide the first physiological evidence that CD38 is required for endogenous NAADP generation in response to CCK stimulation. Furthermore, CD38 expression in CD38-deficient pancreatic AR42J cells remodels Ca²⁺-signaling pathways in these cells by restoring Ca²⁺ mobilization from lysosomes during CCK-induced Ca²⁺ signaling. In agreement with an intracellular site for messenger synthesis, we found that CD38 is expressed in endosomes. These CD38-containing vesicles, likely of endosomal origin, appear to be proximal to lysosomes but not co-localized with them. We propose that CD38 is an NAADP synthase required for coupling receptor activation to NAADP-mediated Ca²⁺ release from lysosomal stores in pancreatic acinar cells.     

Latitudinal gradients and the shaping of life‐history traits in a gregarious caterpillar

The present study aimed to investigate how the impact of several factors linked to geography would shape life‐history traits in a gregarious species, using the pine processionary moth (PPM) Thaumetopoea pityocampa as a model system. PPM has a wide geographical distribution over the Mediterranean Basin, and it is a strictly gregarious species throughout larval development, where the total reproductive output of each female forms a colony. We reviewed both published and unpublished data on PPM from all over its distribution in the Mediterranean Basin and extracted data on fecundity, egg size, egg parasitoid mortality, flight period, and development time. These life‐history traits were then related to location, expressed as latitude and altitude, local average temperatures, and host tree species. We found that PPM fecundity increaseed with latitude, concomitant with an increase in the length of development and an earlier onset of adult flight. These results are the opposite of that found in other Lepidoptera species with a wide geographical distribution, as well as in insects in general. We propose that a large colony size in PPM is important at higher latitudes because this confers an advantage for thermoregulation and tent building in areas where larvae have to face harsher conditions during the winter, thus shifting the optimal trade‐off between the number and size of eggs with latitude. However, host tree species also affected the relationship between egg number and size and the optimal outcome of these traits is likely a compromise between different selection pressures. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100 , 224–236.